Class AbstractIntegrator

    • Field Detail

      • stepHandlers

        protected java.util.Collection<StepHandler> stepHandlers
        Step handler.
      • stepStart

        protected double stepStart
        Current step start time.
      • stepSize

        protected double stepSize
        Current stepsize.
      • isLastStep

        protected boolean isLastStep
        Indicator for last step.
      • resetOccurred

        protected boolean resetOccurred
        Indicator that a state or derivative reset was triggered by some event.
    • Constructor Detail

      • AbstractIntegrator

        public AbstractIntegrator​(java.lang.String name)
        Build an instance.
        Parameters:
        name - name of the method
      • AbstractIntegrator

        protected AbstractIntegrator()
        Build an instance with a null name.
    • Method Detail

      • getName

        public java.lang.String getName()
        Get the name of the method.
        Specified by:
        getName in interface ODEIntegrator
        Returns:
        name of the method
      • addEventHandler

        public void addEventHandler​(EventHandler handler,
                                    double maxCheckInterval,
                                    double convergence,
                                    int maxIterationCount)
        Add an event handler to the integrator. Uses a default UnivariateSolver with an absolute accuracy equal to the given convergence threshold, as root-finding algorithm to detect the state events.
        Specified by:
        addEventHandler in interface ODEIntegrator
        Parameters:
        handler - event handler
        maxCheckInterval - maximal time interval between switching function checks (this interval prevents missing sign changes in case the integration steps becomes very large)
        convergence - convergence threshold in the event time search
        maxIterationCount - upper limit of the iteration count in the event time search
        See Also:
        ODEIntegrator.getEventHandlers(), ODEIntegrator.clearEventHandlers()
      • addEventHandler

        public void addEventHandler​(EventHandler handler,
                                    double maxCheckInterval,
                                    double convergence,
                                    int maxIterationCount,
                                    UnivariateSolver solver)
        Add an event handler to the integrator.
        Specified by:
        addEventHandler in interface ODEIntegrator
        Parameters:
        handler - event handler
        maxCheckInterval - maximal time interval between switching function checks (this interval prevents missing sign changes in case the integration steps becomes very large)
        convergence - convergence threshold in the event time search
        maxIterationCount - upper limit of the iteration count in the event time search
        solver - The root-finding algorithm to use to detect the state events.
        See Also:
        ODEIntegrator.getEventHandlers(), ODEIntegrator.clearEventHandlers()
      • getCurrentStepStart

        public double getCurrentStepStart()
        Get the current value of the step start time ti.

        This method can be called during integration (typically by the object implementing the differential equations problem) if the value of the current step that is attempted is needed.

        The result is undefined if the method is called outside of calls to integrate.

        Specified by:
        getCurrentStepStart in interface ODEIntegrator
        Returns:
        current value of the step start time ti
      • getCurrentSignedStepsize

        public double getCurrentSignedStepsize()
        Get the current signed value of the integration stepsize.

        This method can be called during integration (typically by the object implementing the differential equations problem) if the signed value of the current stepsize that is tried is needed.

        The result is undefined if the method is called outside of calls to integrate.

        Specified by:
        getCurrentSignedStepsize in interface ODEIntegrator
        Returns:
        current signed value of the stepsize
      • setMaxEvaluations

        public void setMaxEvaluations​(int maxEvaluations)
        Set the maximal number of differential equations function evaluations.

        The purpose of this method is to avoid infinite loops which can occur for example when stringent error constraints are set or when lots of discrete events are triggered, thus leading to many rejected steps.

        Specified by:
        setMaxEvaluations in interface ODEIntegrator
        Parameters:
        maxEvaluations - maximal number of function evaluations (negative values are silently converted to maximal integer value, thus representing almost unlimited evaluations)
      • getMaxEvaluations

        public int getMaxEvaluations()
        Get the maximal number of functions evaluations.
        Specified by:
        getMaxEvaluations in interface ODEIntegrator
        Returns:
        maximal number of functions evaluations
      • getEvaluations

        public int getEvaluations()
        Get the number of evaluations of the differential equations function.

        The number of evaluations corresponds to the last call to the integrate method. It is 0 if the method has not been called yet.

        Specified by:
        getEvaluations in interface ODEIntegrator
        Returns:
        number of evaluations of the differential equations function
      • initIntegration

        protected void initIntegration​(double t0,
                                       double[] y0,
                                       double t)
        Prepare the start of an integration.
        Parameters:
        t0 - start value of the independent time variable
        y0 - array containing the start value of the state vector
        t - target time for the integration
      • setEquations

        protected void setEquations​(ExpandableStatefulODE equations)
        Set the equations.
        Parameters:
        equations - equations to set
      • getExpandable

        protected ExpandableStatefulODE getExpandable()
        Get the differential equations to integrate.
        Returns:
        differential equations to integrate
        Since:
        3.2
      • getEvaluationsCounter

        @Deprecated
        protected Incrementor getEvaluationsCounter()
        Deprecated.
        as of 3.6 replaced with getCounter()
        Get the evaluations counter.
        Returns:
        evaluations counter
        Since:
        3.2
      • integrate

        public abstract void integrate​(ExpandableStatefulODE equations,
                                       double t)
                                throws NumberIsTooSmallException,
                                       DimensionMismatchException,
                                       MaxCountExceededException,
                                       NoBracketingException
        Integrate a set of differential equations up to the given time.

        This method solves an Initial Value Problem (IVP).

        The set of differential equations is composed of a main set, which can be extended by some sets of secondary equations. The set of equations must be already set up with initial time and partial states. At integration completion, the final time and partial states will be available in the same object.

        Since this method stores some internal state variables made available in its public interface during integration (getCurrentSignedStepsize()), it is not thread-safe.

        Parameters:
        equations - complete set of differential equations to integrate
        t - target time for the integration (can be set to a value smaller than t0 for backward integration)
        Throws:
        NumberIsTooSmallException - if integration step is too small
        DimensionMismatchException - if the dimension of the complete state does not match the complete equations sets dimension
        MaxCountExceededException - if the number of functions evaluations is exceeded
        NoBracketingException - if the location of an event cannot be bracketed
      • setStateInitialized

        protected void setStateInitialized​(boolean stateInitialized)
        Set the stateInitialized flag.

        This method must be called by integrators with the value false before they start integration, so a proper lazy initialization is done automatically on the first step.

        Parameters:
        stateInitialized - new value for the flag
        Since:
        2.2
      • acceptStep

        protected double acceptStep​(AbstractStepInterpolator interpolator,
                                    double[] y,
                                    double[] yDot,
                                    double tEnd)
                             throws MaxCountExceededException,
                                    DimensionMismatchException,
                                    NoBracketingException
        Accept a step, triggering events and step handlers.
        Parameters:
        interpolator - step interpolator
        y - state vector at step end time, must be reset if an event asks for resetting or if an events stops integration during the step
        yDot - placeholder array where to put the time derivative of the state vector
        tEnd - final integration time
        Returns:
        time at end of step
        Throws:
        MaxCountExceededException - if the interpolator throws one because the number of functions evaluations is exceeded
        NoBracketingException - if the location of an event cannot be bracketed
        DimensionMismatchException - if arrays dimensions do not match equations settings
        Since:
        2.2